The invention relates to a fuselage structure, in particular to a fuselage structure for use in aircraft construction.
Present fuselage structures of conventional transport aircraft usually comprise stiffened panels that are reinforced by circumferential ribs (or frame elements), wherein the ribs (or frame elements) are connected to the fuselage shell by clips (shear clips). Usually clips are riveted to the aircraft shell, to the frame and in some cases to stringers. These clips are used to transfer loads between the aircraft shell and the rib.
In fuselage assembly, in future a welding method will be used to join fuselage panels in longitudinal direction. The weld joint can for example be a butt joint or an overlapping joint that replaces the conventional riveted overlapping connection. The region of the longitudinal connection, irrespective as to whether it is welded or riveted, has to be fastened to the rib with the use of a suitable clip.
However, the use of a conventional clip may not be suitable if fuselage panels in longitudinal direction are connected to the outer shell of an aircraft by welding. The conventional construction of the clips may mean that during the assembly of the outer shell of the fuselage the clips and ribs are installed by rivets in all locations that are positioned away from the longitudinal seams of the panels. The stiffened outer shell or the panels are then connected in longitudinal direction by a suitable welding technique. After welding, the clip is installed in the weld region. This may result in a less than optimal manufacturing sequence because it may be necessary to carry out the riveting procedure twice.
Furthermore in the conventional construction of the clips the weld seam may not be accessible to perform local surface treatment (e.g. corrosion protection). It may be necessary to perform surface treatment of the weld seam before the clips are installed in the weld region. The fuselage panels may have to be protected against corrosion and, by suitable surface treatment, may have to be prepared for varnishing. Surface treatment may have to be performed before the ribs and the clips are installed; however, global treatment of the weld surface may have to take place only after welding. Riveting, welding and surface treatment may thus be separate manufacturing steps so that in the case of the conventional construction of the clips it may be necessary to alternate between these steps, which is time consuming and costly.